1. Field of the Invention
The present invention relates generally to a magnet card type lock. More particularly, the present invention relates to an improvement of the magnet card type lock which assures that the lock is constructed with smaller dimensions and that a locking/unlocking operation can be performed easily and conveniently.
2. Description of the Related Art
A conventional magnet card type lock is constructed in the form of a bank lock as disclosed in for example, Japanese Unexamined Patent Publication (Kokai) NO. 59-173473. This bank lock includes a plurality of magnet tumblers arranged on a common plane so that an unlocking operation is performed by magnetic engagement of permanent magnets on a magnetic card with the magnet tumblers and a locking operation being performed by magnetic disengagement of the former from the latter.
Generally, the conventional magnet card type lock includes a movable member adapted to be engaged with the magnet tumblers in the same manner as the aforementioned bank lock. When a magnet card is inserted into a key hole slit, the movable member is disengaged from the magnet tumblers. Subsequently, the movable member is actuated by a user's fingers so as to unlock a hook or the like which is operatively associated with the movable member.
However, with respect to the conventional magnet card type lock constructed in the above-described manner, it has been found that it has a drawback that it can not practically be employed for a small lock to be equipped on, e.g., a trunk case or the like, since the movable member including a large hook portion is a necessary part of the lock, resulting in the magnet card type lock being designed and constructed in large dimensions.
In addition, since a considerably large magnitude of force given by the user's fingers is exerted directly on the magnet tumblers for bringing the movable member into an unlocked state, another drawback of the conventional magnet card type lock is that the lock is easily broken. In other words, the conventional magnet card type lock provides a low resistance to a violent and malicious unlocking or breaking of the lock with a persons's hands.
Additionally, since two operations, i.e. insertion of the magnet card and actuation of the movable member are required for performing the locking and unlocking operations, or at least for performing the unlocking operation, another drawback of the conventional magnet card type lock is that it is inconvenient to use.